Recyclers who want the flexibility of baling a wide range of materials – from paper to old corrugated cardboard, plastic bottles, used beverage containers and even scrap metal extrusions – and want to make bales that are nearly identical in size every time, should be considering a two-ram baler, say the processors who use them and the companies that produce them. In this type of configuration, one ram compresses the material against a wall and into the path of a second ram. As the second ram pushes the material out, it forms a bale, is tied off and continues out of the baler through the ejection nozzle.
Due to its design, a two-ram baler has a reputation of being tough and able to handle many high-volume baling applications. Because of the dual-ram action, the two-ram normally has a larger hopper and corresponding charge box than a single-ram baler. This allows the baler to accept more bulky material. Single-ram balers are limited by the width of the bale, which is normally 43 inches, so the single-ram hopper can only be that wide.
In a two-ram configuration, the width of the hopper is also the length of the bale, which is normally 60 inches (unless the two-ram baler is a narrow-box model, which only has a 43-inch wide hopper). Therefore, two-ram baler hoppers can be as large as 60 inches wide by 110 inches long. Bale size is normally fixed, with the most common size being 45 inches wide by 30 inches high by 60 inches long.
The larger hopper also allows the processor to use wider and faster conveyors to feed the baler. Many manufactures say that this eliminates the need for a fluffer or shredder to pre-condition the material before it enters the charge box, providing cost savings. More energy savings can be realized if a pre-press is added to push material below the shear blade.
“This is an add-on that has been proven on single-ram balers for years,” says one manufacturer. “Now we are taking those proven technologies and applying them to two-ram models.”
Since the main compression ram in the two-ram baler bales against a wall and not against another bale as in a single-ram extrusion baler, proponents claim that the two-ram makes a denser bale. “The ram of a single-ram baler simply does not go in far enough,” says one manufacturer of both single- and two-ram models. “And there isn’t a wall to bale against.”
Another advantage manufacturers point out is that two-rams make more precise bales than single-ram extrusion balers. “Bales made with a two-ram load better than those from a single-ram baler,” says another manufacturer.
Many processors agree. “We have many types of balers,” says one large processor, “and with my two-ram, I don’t have to worry about the bale sizes – they are perfect every time, and that makes shipping a snap. With our single-ram bales, it is always a challenge when it comes to loading them because the sizes differ.”
All Tied Up
BALING MORE GRADES
Processors who purchase two-ram balers say they buy them mainly to bale material that simply can’t be baled in a single-ram baler, or because material bales better in a two-ram model. These processors point to UBCs, steel cans, plastic bottles and extrusions.
“You can bale plastic bottles and UBCs in a single-ram, but you can bale them better in a two-ram,” says one processor. “We bale a lot of paper, and we have single-rams for that purpose, but we also bale a lot of plastic bottles, and we are using the two-ram baler to do that.”
Baling plastic bottles, particularly, seems to have the edge in a two-ram, according to processors. “We have baled plastic bottles in a single-ram and there is just too much
in the bale,” says another processor. “That’s because you are using annealed wire that is not as stiff as the high tensile wire used in two rams. Plus, with a single ram, you are only applying five bands. With a two ram you can add more as needed, but you usually don’t need to add.”
Probably the biggest advantage of a two-ram is its ability to handle scrap metal extrusions. Because a single-ram extrusion bales one bale against another, extrusions would poke into the bale ahead, causing it to loosen or break. Since a two-ram bales against a wall, this problem is avoided.
Two-ram baler capacities can be as high as 55 tons per hour for paper, 15 to 30 tons per hour for OCC, about 10 to 16 tons per hour for UBCs, and 4 to 12 tons per hour of plastic bottles.
While creating identically-sized bales is an advantage of a two-ram baler, it is also a limitation, because it is not easy to adjust the size of a bale, and that can be important if the mill changes its requirements. Also, if there is not enough material to make a bale, the operator has to make a contaminated bale, clean out the baler or wait for more material, say processors.
However, several two-ram manufacturers have found a way to solve this problem. These companies have installed a door near the end of the ejection nozzle that can close to separate material and hold a bale in place so that more can be added to it. “If you have 50 or 100 pounds of material left over, it’s not enough for another bale, so the door allows you to add that extra material to the existing bale,” says the manufacturer. “With this feature, bales can be oversized by 25 percent – about 9 inches larger than normal.”
The door is near the ejection module, and when an oversized bale is to be made, the door clamps the first part of the bale as it is being banded and ejected. As the door holds the bale in place, more material can be added to the end of it.
“Bale size diversity has traditionally been a limitation of the two-ram baler,” says one manufacturer. “Now, two rams can offer size flexibility, too.”
Another limitation can be the operation of the baler itself. While manufactures say two-rams are designed to run in the automatic mode, processors are saying that they usually have to have an operator nearby to address jams and other concerns.
COST TO OPERATE
Overall, the cost of a two-ram can be anywhere from a low of $100,000 to a high of $500,000, depending on the model. Comparing a single-ram and two-ram with the same output, you will probably pay more for the two-ram.
Operational costs of a two-ram baler should also be considered. The two-ram costs more to operate because of the additional ram and because of the greater baling pressures required. But proponents of the two-ram say that, overall, operating costs are comparable to that of a single-ram extrusion baler because the processor does not need to power a fluffer or shredder due to the large hopper. Manufacturers also say that advances in motor and hydraulic efficiency have narrowed the gap, and some have added pre-presses to reduce shearing pressures.
Wire costs need to be managed more on a two-ram baler. One manufacturer’s representative says that when he inspected bales from two rams he found a wide disparity of banding. “Some had seven straps of wire, some eight and others nine and even 10 straps,” he says. “Even though these balers have auto tie systems, the operator can slap on extra ties, and each tie adds cost to the bale. Some of these bales have more money tied up in the wire than they do in the content.”
But in the normal baling mode, it appears that the wire costs are not that much different from one type of baler to the next. “We only use five straps on our horizontal baler, but they are going around a bale that is 72 inches long,” says one processor that has several material recovery facilities. “We use more wire straps on the two-ram, but they go around the width, so it ends up being about the same amount of wire usage for each in the end.”